During operation, conventional circuit boards both radiate and conduct electromagnetic radiation. In a phenomenon known as electromagnetic interference (EMI), electromagnetic radiation generated by a circuit board can affect the function of other electronic devices (e.g., other circuit boards) in the vicinity of the circuit board. Also, electromagnetic radiation generated by the other electronic devices can affect the function or performance of the circuit board. EMI shielding devices help reduce emitted electromagnetic radiation from the radiation sources and also help protect the circuit board against electromagnetic radiation emissions from other radiation sources.
In conventional computer systems, the circuit boards include shielding elements that provide electromagnetic isolation from other electronics devices (e.g., circuit boards) in the computer system, thereby minimizing the effect of EMI on the circuit boards. For example, conventional circuit boards include carrier trays or supports. Each carrier tray typically covers a substantial portion of the associated circuit board. The carrier trays are formed of a metallic or electrically conductive material and, when grounded with an electrically conductive chassis of a computer system, attenuate or redirect EMI radiation relative to the circuit boards.
For example, the circuit board and carrier tray typically insert within a chassis of the computer system via card guides. The card guides provide grounding between the carrier tray and chassis to attenuate or redirect EMI radiation relative to the circuit board. For example, in one arrangement, a manufacturer integrally forms the card guides as part of the chassis using a stamping process. As a user inserts the circuit board and carrier tray into the stamped card guides, the carrier tray electrically contacts the stamped metal card guides. Such contact attenuates EMI radiation relative to the circuit board. In another example, a manufacturer uses a beryllium copper gasket in conjunction with the card guides of the computer device to provide grounding of the carrier tray to the chassis. A manufacturer attaches the beryllium copper gasket to the card guides using an adhesive. As a user inserts a circuit board and carrier tray into the card guides, the carrier tray electrically contacts the beryllium copper gasket. Such contact attenuates EMI radiation relative to the circuit board.